Cierroannee44
On sbb.ch, check under ‘Orders’ at the top of the screen below your initials / profile, then select last year as period. All your order history should appear here, and there’s a refund button where applicable.
(BTW, why ordering a STP THAT far in advance? There is no, zilch, nada advantage doing so instead of getting it at the same price at the airport travel centre, once you successfully made it there…)